Dermatology Book

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Tinea Capitis

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  1. Causative Organisms
    1. Trichophyton tonsurans (90-95% of U.S. cases)
    2. Microsporum canis
  2. Epidemiology
    1. Most common in
      1. Children ages 4-14 years
      2. Low socioeconomic groups
    2. Contagious Spread
      1. Easily spread by fomites or hair
      2. Person to Person Spread
        1. Non-Inflammatory Tinea Capitis
        2. Black dot Ringworm
      3. Spread from cats, dogs, and soil
        1. Inflammatory Tinea Capitis
  3. Differential Diagnosis
    1. Scaling and Inflammation predominant
      1. Seborrheic Dermatitis
      2. Atopic Dermatitis
      3. Psoriasis
      4. Impetigo
      5. Cellulitis
    2. Alopecia predominant
      1. Discoid Lupus
      2. Syphilis
      3. Alopecia Areata
      4. Trichotillomania
  4. Symptoms
    1. Pruritus (especially in Inflammatory Tinea Capitis)
  5. Signs
    1. General findings
      1. Circumscribed areas of Alopecia
      2. Boggy, raised lesion
        1. Rim of erythema (variable)
        2. Fine scale
      3. Microsporum lesions fluoresce under Wood's Lamp
        1. Trichophyton (92% of cases) does not fluoresce
        2. Hence most cases of tinea capitis do not fluoresce
    2. Non-inflammatory (epidemic) Tinea Capitis
      1. Hair gray or lusterless
      2. Hair breaks above scalp
      3. Wood's Lamp: Fluorescent
    3. Inflammatory Tinea Capitis
      1. Scalp red with Pustules or kerion
        1. Psoriasis appearance, but hairs are broken off
      2. Fever
      3. Lymphadenopathy
      4. Wood's Lamp: Fluorescent
    4. Black dot Ringworm
      1. Hair breaks off at skin level
        1. Scalp studded with tiny black dots
      2. Wood's Lamp: Not Fluorescent
  6. Diagnosis: Criteria for empiric treatment
    1. Criteria: Three or more of the following present
      1. Scalp Scaling
      2. Alopecia
      3. Occipital adenopathy
      4. Scalp Pruritus
    2. Interpretation
      1. Findings highly suggestive of tinea capitis in child
      2. Test Sensitivity: 92% (but small study)
      3. Justifies empiric tinea capitis therapy
    3. References
      1. Hubbard (1999) Arch Pediatr Adolesc Med 153:1150
  7. Complications: Kerion
    1. Allergic sensitization to fungus
    2. Results in Alopecia if untreated
  8. Labs
    1. Potassium Hydroxide (KOH)
    2. Hair Fungal Culture
  9. Management
    1. General
      1. Most Antifungal Medications require lab monitoring
      2. See specific agents for details
    2. First Line: Terbinafine
      1. Adult (and child >40 kg): 250 mg PO qd
      2. Child 20-40 kg: 125 mg PO qd
      3. Child <20 kg: 67.5 mg PO qd
      4. Treat for 4 weeks for Trichophyton tonsurans
      5. Treat for 4-8 weeks for Microsporum canis
    3. Alternative Agents
      1. Fluconazole 8 mg/kg each week for 8-12 weeks
      2. Itraconazole 3-5 mg/kg/day for 4 weeks
      3. Griseofulvin
        1. Adults: 500 mg PO qd for 4-6 weeks
        2. Child: 10-20 mg/kg/day until Hair Growth (8 weeks)
    4. Concurrent Topical Antifungal reduces transmission
      1. Apply for 5 minutes twice each week
      2. Agents
        1. Selenium Sulfate (OTC 1% is effective) or
        2. Topical Ketoconazole or
        3. Povidone iodine lotion or shampoo
    5. Kerion
      1. Prednisone 1 mg/kg/d or
      2. Topical Triamcinolone 0.1% Cream
  10. References
    1. Gilbert (2001) Sanford Guide to Antimicrobials
    2. Nesbitt (2000) Int J Dermatol 39(4):261

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